The present invention relates generally to two-wheeled vehicles. More particularly, the present invention relates to a rear suspension system for two-wheeled vehicles, such as motorcycles, employing pivoting arm assemblies and control arm possessing shock absorption characteristics and providing lateral stability.
The existing designs of most prior art rear suspension assemblies for two-wheeled vehicles include a rear pivot from a single point either from a dual or mono shock system that either extends or comprises the shock unit. In this respect, when the shock system is affected by power or braking to the rear wheel, system efficiency and stability are compromised. Other systems use a quad-type configuration that only connects to a small section of the frame, providing less structural integrity.
Although recent motorcycle frames include a swing arm configuration, these configurations posses certain deficiencies that detract from their overall utility. The swing arm movement is typically in a pivoting motion upwardly and directed towards the front part of the motorcycle. This causes lateral instability for the rear wheel of the motorcycle. Many existing suspension systems provide inadequate control of the wheel to pavement contact. This can create safety concerns regarding the control of the increased stopping during braking. Aside from the rear wheel wobbling, as described above, many current designs transfer force back to the front of the vehicle under acceleration.
Accordingly, there is a need for a rear suspension system for a two-wheeled vehicle which improves rear wheel geometry. Such a system should also increase lateral stability of the rear wheel of the vehicle and improve wheel contact with the pavement. Such a system should further contain the power under acceleration and not transfer force back to the front of the vehicle. The present invention fulfills these needs and provides other related advantages.
The present invention relates to a rear suspension system for two-wheeled vehicles. The system includes first and second spaced apart and parallel support axle plates. The first and second support axle plates include aligned apertures configured to receive an axle of a rear wheel of the two-wheeled vehicle, such as a motorcycle.
An upper arm assembly is pivotally connected at a first end thereof to a vehicle frame, and at a second end thereof to the first and second support axle plates. The upper arm assembly is comprised of a base pivotally connected to the vehicle frame. A first elongated arm extends from the base to a pivotal connection point at the first support axle plate. A second elongated arm extends from the base generally parallel to the first arm to a pivotal connection point at the second support axle plate.
First and second control arms are pivotally connected at the respective first ends to the upper arm assembly, typically intermediate the ends of the first and second arms.
A lower arm assembly is pivotally connected at a first end thereof to the first and second support axle plates, and pivotally connected at a second end thereof to second ends of the first and second control arms. The lower arm assembly includes a base having a first elongated arm extending therefrom to a pivotal connection point at the first support axle plate. A second elongated arm extends from the base generally parallel to the first arm to a pivotal connection point at the second support axle plate.
A pivot arm assembly is pivotally connected at a first end to the vehicle frame, and at a second end to the first and second control arms. The pivot arm assembly comprises a pair of angular brackets spaced apart and generally parallel to one another and having a shaft extending between first ends thereof for pivotal connection to the vehicle frame. A shaft extends through second ends thereof for pivotal connection to the first and second control arms, intermediate the ends thereof.
A compressible shock unit is associated at one end with the lower arm assembly or pivot arm assembly, and connected at the opposite end thereof to the vehicle frame. In a particularly preferred embodiment, the shock unit is pivotally connected to the base of the lower arm assembly at one end, and pivotally connected to the vehicle frame at the other end of the shock unit generally opposite the lower arm assembly. The above-described system has a generally triangular configuration. With the system of the present invention, lateral stability is created for the rear wheel of the two-wheeled vehicle.
Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.